You are 9 years in US and forgot to take Visas of your children while traveling!! What did you think? Your children can do anything as they were born on USA, having US passports. The immigration officers have done their job. You guys are following the rules strictly at USA and expect Indian immigration officers will break the rules for your stupidness. Forget about India. Your childrens are US citizen. You will be so within couple of years. Live happily at your dream land.